Ultralow Threshold Surface Emitting Ultraviolet Lasers with Semiconductor Nanowires

Abstract

Abstract Surface-emitting semiconductor lasers have changed our everyday life in various ways such as communication and sensing. Expanding the operation wavelength of surface-emitting semiconductor lasers to shorter ultraviolet (UV) wavelength range further broadens the applications to disinfection, medical diagnostics, phototherapy, and so on. Nonetheless, the UV surface-emitting lasers demonstrated so far are all using conventional vertical cavities, all with large lasing thresholds in the range of several hundred kW/cm^2 to MW/cm^2. Here, we report ultralow threshold surface-emitting lasing in the UV range using novel epitaxial nanowire photonic crystal structures. Lasing at 367 nm is measured, with a threshold of only 7 kW/cm^2, a factor of 100× reduction compared to the previously reported surface-emitting UV lasers at similar wavelengths. Further given the excellent electrical doping that has already been demonstrated in nanowires, this work offers a viable path for the development of the long-sought-after surface-emitting semiconductor UV lasers.